title: Polymeric nanoparticles for siRNA delivery and gene silencing.
abstract: Gene silencing using small interfering RNA (siRNA) has several potential therapeutic applications. In the present study, we investigated nanoparticles formulated using the biodegradable polymer, poly(d,l-lactide-co-glycolide) (PLGA) for siRNA delivery. A cationic polymer, polyethylenimine (PEI), was incorporated in the PLGA matrix to improve siRNA encapsulation in PLGA nanoparticles. PLGA-PEI nanoparticles were formulated using double emulsion-solvent evaporation technique and characterized for siRNA encapsulation and in vitro release. The effectiveness of siRNA-loaded PLGA-PEI nanoparticles in silencing a model gene, fire-fly luciferase, was investigated in cell culture. Presence of PEI in PLGA nanoparticle matrix increased siRNA encapsulation by about 2-fold and also improved the siRNA release profile. PLGA-PEI nanoparticles carrying luciferase-targeted siRNA enabled effective silencing of the gene in cells stably expressing luciferase as well as in cells that could be induced to overexpress the gene. Quantitative studies indicated that presence of PEI in PLGA nanoparticles resulted in 2-fold higher cellular uptake of nanoparticles while fluorescence microscopy studies showed that PLGA-PEI nanoparticles delivered the encapsulated siRNA in the cellular cytoplasm; both higher uptake and greater cytosolic delivery could have contributed to the gene silencing effectiveness of PLGA-PEI nanoparticles. Serum stability and lack of cytotoxicity further add to the potential of PLGA-PEI nanoparticles in gene silencing-based therapeutic applications.
authors.affiliation: Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Patil
authors.forename: Jayanth
authors.initials: J
authors.lastname: Panyam
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival; D004337:Drug Carriers / Q000737:chemistry*; D005260:Female; D020868:Gene Silencing; D006801:Humans; D007097:Imines / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011095:Polyethylenes / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D013499:Surface Properties; D014162:Transfection
chemical_list: D004337:Drug Carriers; D007097:Imines; D011095:Polyethylenes; D034741:RNA, Small Interfering; C505405:poly(ethylene imine); D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid